Electronic devices, such as semiconductor devices, memory chips, microprocessor chips, and imager chips, can include a set of fuses for storing information. For example, the electronic devices, such as semiconductor dies, can include one or more fuse arrays (e.g., a set or a network of fuses or anti-fuses that are programmed to store information). The electronic devices can include the one or more fuse arrays in a particular location (e.g., a central location), thereby replacing discrete fuses that were located throughout the device in other designs. The semiconductor die can read the information (e.g., redundancy information, wafer lot number, die lot number, die position on the wafer, etc.) from the fuse array and broadcast the information (e.g., based on communicating the information in a serial sequence), such as at device startup, initialization, or configuration.
FIG. 1 is an example circuit diagram of an electronic device 100 (e.g., a semiconductor die) including a fuse array and a fuse read circuit. The electronic device 100 can include one or more fuse arrays 102 that include multiple fuse cells 104 for storing information. For example, each of the multiple fuse cells 104 (e.g., for anti-fuses or gate oxide fuses) can include a setting circuit 108 (e.g., an oxide layer) that can be configured to represent information (e.g., for providing an open circuit when the cell is not programmed or for providing a short, such as through a weakened or damaged oxide layer, when the cell is programmed).
The electronic device 100 can use a fuse read circuit 120 to read the information stored in the one or more fuse arrays 102. To read the stored information, the selection circuit 110 can connect one or more fuse cells, an input source (e.g., a high-output bi-level power source or a variable analog power source) for providing an input power (e.g., ‘Vcc’), or a combination thereof to the fuse read circuit 120. For example, the electronic device 100 can precharge a fuse read-level 122 (e.g., a voltage level, represented as ‘FzCom,’ at a fuse read node 121 connecting the fuse read circuit 120 and the fuse array 102). When the setting circuit 108 is programmed or short, the fuse cell 104 can provide an electrical path (e.g., for dissipating the charge or to a lower potential node) to pull the fuse read-level 122 below the input source voltage. When the setting circuit 108 is not programmed or open, the fuse read node 121 can maintain the fuse read-level 122 at the input source voltage.
The fuse read circuit 120 can include a precharging transistor 124 that operates based on a precharging signal 126 (e.g., a gate voltage for the precharging transistor 124). The fuse read circuit 120 can use the precharging transistor 124 to precharge the fuse read-level 122 to the input source voltage for reading the information represented by the setting of the selected fuse cell. To precharge, the precharging transistor 124 can connect the input source to the fuse read node 121 based on the precharging signal 126.
FIGS. 2A-2C are timing diagrams illustrating the operation of a fuse read circuit. FIGS. 2A-2C illustrate timing of input signals and corresponding output signal behaviors under various programming conditions of the fuse cell 104 of FIG. 1 being read by the fuse read circuit 120 of FIG. 1. For example, FIG. 2A can illustrate a clearly-blown fuse profile 202, FIG. 2B can illustrate a unblown fuse profile 204, and the FIG. 2C can illustrate a weakly-blown fuse profile 206.
The electronic device 100 of FIG. 1 can read the programmed state (e.g., an unprogrammed state represented by an open circuit or a first resistance level, and a programmed state represented by a short circuit or a second resistance level lower than the first resistance level for anti-fuses) of the fuse cell 104 in the fuse array 102 of FIG. 1 using the fuse read circuit 120. The electronic device 100 (e.g., using the fuse read circuit 120, a control circuitry, etc.) can read the programmed state based on precharging the fuse read-level 122 of FIG. 1 at the fuse read node 121 of FIG. 1 (e.g., represented as ‘FzCom’ for FIGS. 2A-2C). To precharge the fuse read node 121, the fuse read circuit 120 can use the precharging signal 126 of FIG. 1, represented as ‘RdFz2F,’ to operate the precharging transistor 124 and connect or route the input source voltage (‘Vcc’) to the fuse read node 121. As illustrated in FIGS. 2A-2C, a negative pulse for the precharging signal 126 having a width of an enable duration 212 can operate the precharging transistor 124 and precharge the fuse read-level 122 to an input source level 234 (e.g., a voltage level of the selected power source/level, represented as ‘Vcc’).
After the enable duration 212, the fuse read-level 122 can change or adjust based on the programming or setting of the fuse cell 104. For the fuse cell 104 that is clearly programmed as a blown state (e.g., with the setting circuit 108 of FIG. 1 providing relatively low resistance to ground ‘Vss’ or lower voltage node for anti-fuses), as illustrated by the clearly-blown fuse profile 202, the electrical charge or the voltage at the fuse read node 121 can dissipate through the relatively low resistive path through the fuse cell 104. Accordingly, the fuse read-level 122 can decrease over time after the enable duration 212.
For the fuse cell 104 that is clearly programmed as an unblown state (e.g., with the setting circuit 108 providing relatively high resistance to ground for anti-fuses), as illustrated by the unblown fuse profile 204, the electrical charge or the voltage at the fuse read node 121 can be retained or maintained since there is no path to dissipate the charge through the fuse cell 104. Accordingly, the fuse read-level 122 can remain at the input source level 234.
The fuse read circuit 120 can determine the setting or the programming of the selected fuse according to the fuse read-level 122 after a reading duration 214. For example, the read-lock signal 134 of FIG. 1 (e.g., represented as ‘RdFzF’ in FIGS. 2A-2C) can go low simultaneously with the precharging signal 126, and remain low for the reading duration 214 after the enable duration 212. During the reading duration 214, the fuse read-level 122 can adjust or settle based on the fuse setting as discussed above. The intermediate output (e.g., represented as ‘Fz’ in FIGS. 2A-2C) can behave complementary to the fuse read-level 122.
At the end of the reading duration 214, the read-lock signal 134 can go high and the fuse read circuit 120 can generate the fuse-read output based on the fuse read-level 122 and/or the intermediate output in relation to a reading threshold 222 (e.g., a threshold voltage level for distinguishing a low-voltage state corresponding to the blown state of the fuse from a high-voltage state corresponds to the unblown state). When the fuse read-level 122 is below the reading threshold 222 (e.g., as illustrated in FIG. 2A for the clearly-blown fuse profile 202), the fuse read circuit 120 can generate the fuse-read output representing the blown state of the corresponding fuse. When the fuse read-level 122 is above the reading threshold 222 (e.g., as illustrated in FIG. 2B for the unblown fuse profile 204), the fuse read circuit 120 can generate the fuse-read output 138 representing the unblown state of the corresponding fuse. For example, the fuse-read output 138 can be asserted high during the enable duration 212 and the reading duration 214, and then asserted low after the read-lock signal 134 goes high if warranted.
Fuse cell programming can result in a variety of settings or effects on the setting circuit 108, and some fuses result in a weakly-blown state. The fuse read-level 122 and the corresponding results can be illustrated in FIG. 2C with the weakly-blown fuse profile 206. For the weakly-blown fuse, the fuse read-level 122 can behave similar to other fuses during the enable duration 212. However, since the weakly blown setting of the setting circuit 108 provides higher resistance than the clearly blown fuses, the fuse read-level 122 decreases at a slower rate than clearly blown fuses. At the end of the enable duration 212, the fuse read-level 122 can still be greater than the reading threshold 222, which can lead to an erroneous value for the fuse-read output 138 (e.g., the fuse-read output 138 is in high voltage state when the fuse was intended to represent a blown state).